1. Field of the Invention
The invention relates to a semiconductor structure, and in particular to a semiconductor structure capable of formation of a continuous pixel electrode.
2. Description of the Related Art
A top view of a conventional semiconductor structure is shown in FIG. 1. FIG. 2A is a cross-section along A-A′ line of FIG. 1. A conventional fabrication method of a semiconductor structure is shown in FIGS. 2A˜2D.
Referring to FIGS. 1 and 2A, a substrate 1 is provided. A first metal line 2 is then formed on the substrate 1. The first metal line 2 may be gate line or common line. Next, an insulation layer 3 is formed on the substrate 1, overlying the first metal line 2. A semiconductor layer 4 is then formed on the insulation layer 3. Next, a second metal line 5 is formed on the semiconductor layer 4. A protective layer 6 is then formed on the second metal line 5. Next, a photoresist layer 7 is formed on the protective layer 6, overlying the first metal line 2 and exposing a portion of the insulation layer 3, the semiconductor layer 4, the second metal line 5 and the protective layer 6.
Referring to FIG. 2B, the protective layer 6, the second metal line 5, the semiconductor layer 4 and the insulation layer 3 are then etched using the photoresist layer 7 as a mask, exposing the substrate 1. The etching rate of the insulation layer 3 is faster than that of the semiconductor layer 4 due to various materials therebetween, resulting in non-continuity, shown as under cut 8.
After removal of a portion of the photoresist layer 7, as shown in FIG. 2C, an indium tin oxide electrode 9 is deposited on the photoresist layer 7, the protective layer 6, the second metal line 5, the semiconductor layer 4 and the substrate 1, as shown in FIG. 2D. However, the indium tin oxide electrode 9 deposited on the substrate 1 is discontinuous with that deposited on other layers because of the undercut, resulting in electrode break 10.